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Main Page   >   Geomagnetic Variations   >    Indices of geomagnetic activity    >

Indices of Geomagnetic Activity

Geomagnetic activity indices are a quantitative measure of geomagnetic activity and are intended to describe variations in the Earth's magnetic field caused by the action of the solar plasma flow (solar wind) on the Earth's magnetosphere, changes within the magnetosphere, and interaction of the magnetosphere and the ionosphere. Each of the indices is calculated from the measurement results and characterizes only a part of the complex picture of the solar and geomagnetic activity.

The existing indices of geomagnetic activity can be conditionally divided into three groups.
The first group includes local indices computed from the data of one observatory and showing the value of the local geomagnetic disturbance: С and K indeces.
The second group includes indices characterizing geomagnetic activity on the whole Earth. These are the so-called planetary indices: Кp, ар, Ар, аm, Am, aa, Aa.
The third group includes indices reflecting the intensity of magnetic disturbances from a well-defined source: Dst, AЕ, РС.

All indices of the geomagnetic activity listed above are computed and published according to the UT world time.

International Association of Geomagnetism and Aeronomy - IAGA (International Association of Geomagnetism and Aeronomy – IAGA) officially recognizes the indices aa, am, Kp, Dst, PC and AE.
More information about IAGA indices is available on the website of the International Service of Geomagnetic Indices (International Service of Geomagnetic Indices – ISGI).

К and С indices.

aa and Аa indices.

Kp, ap and Ap indices.

AU, AL, AE, AO indices.

Dst index.

ASY and SYM indices.

PC index.

Km, Kn, Ks индексы.

am, an, as indices.

Quiet Q and Disturbed D international days.

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